GEOTECHNICAL ENGINEERING REPORT - … ENGINEERING REPORT . ... Figure 2 included at the end of this...

GEOTECHNICAL ENGINEERING REPORT 17th Street Market 100 North 17th Street Richmond, Virginia

Schnabel Reference 16C13048 May 5, 2016 Prepared For: City of Richmond

May 5, 2016 Ms. Jeannie Welliver Department of Economic Development 500 E. Franklin Street, Suite 800 Richmond, Virginia 23219

Subject: Project 16C13048, Geotechnical Engineering Report, 17th Street Market, 100 North 17th Street, Richmond, Virginia

Dear Ms. Welliver: SCHNABEL ENGINEERING, LLC (Schnabel) is pleased to submit our geotechnical engineering report for this project. This study was performed in accordance with our revised proposal dated March 28, 2016, as authorized by your Purchase Order No. 16000018544 dated March 31, 2016 and delivered to our office on April 22, 2016.

PROJECT DESCRIPTION

Site Description

The site is located along N. 17th Street between E. Main Street and E. Franklin Street. The site contains the remnants of the current 17th Street Farmer’s Market and the surrounding north and southbound lanes of N. 17th Street. The current market includes three covered pavilions and parking spaces. North 17th

Street is paved in cobblestones, and the market area is currently covered in concrete and brick pavers. The site is relatively flat with site grades gently sloping downward from about El 20 in the southeast to about El 18 in the north.

We obtained the site information from the site plans by Baskerville dated 02-04-2015, and through our site reconnaissance. A Site Vicinity Map is included as Figure 1.

Proposed Construction

The project includes the construction of a new open air market on the site. The new construction will restrict traffic on N. 17th Street between E. Main Street and E. Franklin Street to emergency and service vehicle access only. The cobblestone pavers and granite curbs from the existing N. 17th Street will be reclaimed and reused for the new construction. The sidewalks along N. 17th Street will be will be extended from 6 ft to 16 ft to allow café style seating for the businesses located on N. 17th Street.

The area between the two lanes of N. 17th Street will be covered in pavers. In addition, the market will have flower beds, trees, benches, tables, chairs, lampposts, and fire pits placed throughout. The planting

City of Richmond 17th Street Market

May 5, 2016 Page 2 Schnabel Engineering, LLC Project 16C13048 ©2016 All Rights Reserved

beds will require the excavation of rectangles of varying size and depth throughout the market. These excavations will be several feet deep where the 6 to 7 inch caliper trees are located within the planting beds. The market will also include retractable bollards along E. Main Street and E. Franklin Street and Walnut Alley to restrict vehicle traffic. Eight steel poles are planned along the outer edge of the market. The poles will support security cameras, speakers, and festoon style lighting. In addition, a lighted in-ground fountain is planned for the center of the market. The fountain will require the construction of an underground control vault that will likely be located on the north or south side of the fountain.

Foundation loads were not available at the writing of this report. However, we assume that spread footings or shallow drilled shafts will be used for the support of the steel poles.

We obtained the project information from the project plans by Baskervill dated 02-04-2015, and from our meeting with you and the designers on February 3, 2016.

SUBSURFACE EXPLORATION AND LABORATORY TESTING PROGRAM

We performed a subsurface exploration and field testing program to identify the subsurface stratigraphy underlying the site and to evaluate the geotechnical properties of the materials encountered. This program included test borings. Exploration methods used are discussed below. The appendices contain the results of our exploration.

Subsurface Exploration Methods

Test Borings

We observed our subcontractor, Ayers & Ayers, Inc., drill six test borings for the project on April 14, 2016. The Standard Penetration Test (SPT) was performed at selected depths in the borings. Appendix A includes specific observations, remarks, and logs for the borings; classification criteria; drilling methods; and sampling protocols. Figure 2 included at the end of this report indicates the approximate test boring locations. We will retain soil samples up to 45 days beyond the issuance of this report, unless you request other disposition.

Soil Laboratory Testing

Our laboratory performed tests on selected samples collected during the subsurface exploration. The testing aided in the classification of materials encountered in the subsurface exploration and provided data for use in the development of recommendations for design of foundations and earthwork, as well as design parameters for below-grade walls and pavements. The laboratory testing included index, compaction, and CBR testing. The results of the laboratory tests are included in Appendix B and are summarized for each stratum in the Site Geology and Subsurface Conditions section of this report. Selected test results are also shown on the boring logs in Appendix A.



SITE GEOLOGY AND SUBSURFACE CONDITIONS

Site Geology

We reviewed existing geologic data and information in our files. Based on this review, the geologic stratigraphy consists of Pleistocene Age upland terrace deposits over residual materials derived from the weathering of the Petersburg granite formation. The terrace deposits are alluvial soils that typically consist of a mixture of clay, silt, sand, and gravel. These soils typically exhibit moderate to high strength and low to moderate compressibility. The residual soils are derived from the chemical and physical weathering of the underlying parent material, the Petersburg granite rock.

The above stratigraphy is typical in the Shockoe Bottom area. However, in the immediate vicinity of the project site, some or all of the above strata have been eroded or excavated, and commonly have been replaced with recent alluvial deposits or fill.

Generalized Subsurface Stratigraphy

We characterized the following generalized subsurface stratigraphy based on the exploration and laboratory test data included in the appendices.

Ground Cover: Pavement

Three different pavement sections were encountered in the borings performed on the site. The first pavement section was encountered in the northern and southern ends of the market, in Borings B-01, B-02, and B-05. This section consisted of 2.5 to 3.5 inches of brick pavers at the ground surface overlying a 1 to 2 inch thick layer of leveling sand below the pavers. Below the leveling sand, there was a 3 to 6 inch thick layer of asphalt over a 4 to 5 inch thick layer of dense graded aggregate.

The second pavement section was encountered in the center of the market, in Borings B-03 and B-04. This section consisted of a 4.5 to 5.5 inch thick layer of concrete over 3 to 5.5 inches of asphalt. There was a 5 to 7 inch thick layer of dense graded aggregate below the asphalt.

The third pavement section was encountered in Boring B-06, and consisted of a 24 inches of concrete.

Stratum A: Existing Fill

Below the ground cover, the borings encountered existing fill soils consisting of sandy fat clay, sandy lean clay, clayey sand, silty sand, and poorly graded sand with silt (CH, CL, SC, SM, SP-SM) with varying amounts of gravel, crushed stone, brick fragments, and wood fragments to depths of 2.6 to 18.5 ft, El 0.5 to 17.4. The samples of soil tested from Stratum A were of low to high plasticity having liquid limits of 32 and 64, and plasticity indices of 11 and 39. The natural moisture contents measured were about 5 to 37 percent. Based on the Standard Penetration Tests performed, this stratum is generally soft to hard consistency and loose to dense: N = 3 to 34.

Laboratory tests performed on samples representing Stratum A indicate these soils exhibit a low to high potential for moisture-related volume change (shrink/swell behavior).



It should be noted that Borings B-04 and B-06 contained a layer of non-woven geotextile within the existing fill soils at depths of 3 and 4.2 ft. This geotextile was likely used as a soil improvement technique to remediate the loose or soft layers of existing fill prior to placement of the current paving materials.

Stratum B: Alluvium

Below the fill soils of Stratum A, Boring B-05 encountered an alluvial deposit consisting of clayey sand (SC) with minor amounts of organic matter to a depth of 18.5 ft, El -0.5. The natural moisture content measured was about 21 percent. Based on the Standard Penetration Tests performed, this stratum is generally very loose to loose: N = 3 to 7.

Stratum C: Terrace

Below the fill soils of Stratum A, Borings B-01 through B-04 encountered a terrace deposit consisting of clayey sand and clayey gravel with sand (SC, GC) to depths of 5.3 to 22.5 ft, El -3.5 to 14.7. The sample of soil tested from this stratum was of moderate plasticity having a liquid limit of 39, and a plasticity index of 25. Based on the Standard Penetration Tests performed, this stratum is generally medium dense to very dense: N = 28 to 50/5”.

Laboratory tests performed on samples representing Stratum C indicate these soils exhibit a low potential for moisture-related volume change (shrink/swell behavior).

We performed a Standard Proctor Compaction test and a CBR test on a bulk sample representing this stratum. The sample consisted of clayey sand with gravel, and classified (SC)/(A-2-6) in accordance with ASTM and AASHTO classification systems. The compaction test resulted in a maximum dry density of 126.5 pcf at an optimum moisture content of 9.2 percent. The natural moisture content value of this sample of soil tested in our laboratory was about 15 percent, or 6 percentage points above the optimum value. We obtained a laboratory CBR value of 10.8 with a swell value of 0.8 percent for this sample.

Stratum D: Residuum

Below the soils of Strata A, B, and C, the borings encountered residual soils derived from the Petersburg Granite formation consisting of silty sand (SM) with varying amounts of mica to the maximum depth of exploration, 25 ft. The sample of soil tested from this stratum was of high plasticity having a liquid limit of 63, and a plasticity index of 24. The natural moisture contents measured were about 23 percent. Based on the Standard Penetration Tests performed, this stratum is loose to dense: N = 8 to 43.

Laboratory tests performed on samples representing Stratum D indicate these soils exhibit a low potential for moisture-related volume change (shrink/swell behavior).

Groundwater

At our direction, the drilling subcontractor installed a water observation well in Boring B-03. We observed groundwater in this well at a depth of 8 ft (about EL 12) 20 days after completion of the boring. We also observed groundwater in Borings B-04 and B-05 at depths of 10 to 13.5 ft, about EL 5.5 to 8 immediately after removing the augers. The remaining borings caved dry at depths of 5 to 9 ft.



The test boring logs in Appendix A include groundwater observations obtained during our subsurface exploration. These data include depths to groundwater encountered during drilling, upon drilling completion, and following completion of the boring.

Other than at Boring B-03, we did not obtain long-term water level readings in the remaining borings since we backfilled them upon completion for safety.

The groundwater levels on the logs indicate our estimate of the hydrostatic water table at the time of our subsurface exploration. The final design should anticipate the fluctuation of the hydrostatic water table depending on variations in precipitation, surface runoff, pumping, tidal action, evaporation, leaking utilities, stream levels, and similar factors.

Seismic Site Classification

We evaluated the Seismic Site Class and Seismic Site Coefficients for this project according to the International Building Code (IBC) Section 1615 (2012). Our analysis indicates Site Class D for this location. This Site Class was evaluated based on corrected SPT values.

GEOTECHNICAL RECOMMENDATIONS

We based our geotechnical engineering analysis on the information developed from our subsurface exploration and soil laboratory testing, along with the project development plans, site plans, and structural loading furnished to our office. We recommend short drilled shafts or shallow spread footings for support of the proposed tapered steel poles based on our analysis. The following sections of the report provide our detailed recommendations.

Site Grading and Earthwork

The proposed fountain and landscaping features will require cuts of up to 5 ft within the proposed market development. Minimal amounts of compacted structural fill are anticipated. Recommendations for compacted fill subgrade preparation, fill soil requirements, and placement and compaction criteria are presented in subsequent sections.

Compacted Fill Subgrades

Subgrades to receive compacted structural fill for foundation or pavement support should be stripped of existing pavements. Our subsurface exploration indicated pavement to depths of 1 to 2 ft below the ground surface.

Compacted structural fill subgrades should consist of suitable soils of Strata A or C. These soils are expected to be encountered at shallow depths beneath the pavement, except possibly in the northwestern section of the market. Very loose or soft unsuitable fill soils were encountered in Boring B-05 just below the existing pavement section. Soft, loose Stratum A soils, and Stratum A soils that contain organic or other deleterious materials are not considered suitable for direct support of the proposed foundations or pavements. When encountered at new foundation or pavement subgrade levels these soils will require some remediation. Remediation of these subgrades could include undercut and replacement with new compacted structural fill meeting the requirements outlined below; scarifying,



drying, and compacting the surface of the existing fill soils; placement of a geotextile reinforcing layer; or some combination of these alternatives.

The Geotechnical Engineer should evaluate the suitability of the fill subgrades. The stripped subgrades should be proofrolled with a loaded dump truck to evaluate the subgrade suitability for support of the compacted structural fill prior to any undercutting or initiation of fill placement. Areas that exhibit excessive pumping, or rutting should be scarified, dried and recompacted, or undercut and replaced with compacted structural fill as recommended by the Geotechnical Engineer. Subgrade evaluation techniques complementary to proofrolling could include a combination of probing with a penetrometer, drilling hand augers, or observing test pits.

Depending on the conditions encountered in the field, we may recommend stabilizing subgrades through the use of a geogrid, such as Tensar TriAx® TX140, or equivalent. Subgrades may also be stabilized with a geosynthetic separation fabric, such as Mirafi 500X, or equivalent. Specific recommendations regarding the use of geotextiles and select fill materials will be provided by the Geotechnical Engineer during construction and will depend on the conditions exposed in the field. We recommend including line items in the bid documents for installed quantities on a per unit basis. When removal of unsuitable materials is required, the excavation should be performed in a manner to limit disturbance of the underlying suitable material. The excavation should be performed under the observation of the Geotechnical Engineer to evaluate required excavation depths. Undercut volumes should be evaluated by cross sectioning. Other methods of calculating volumes of undercut, such as counting trucks, are less accurate and generally result in additional expense. If truck counts are used, we recommend the method of payment be in accordance with Section 109 of VDOT Road and Bridge Specifications.

If stripping and earthwork operations are performed during an extended period of warm, dry weather, the non-organic portions of the undercut materials may be reused as compacted structural fill. It should be noted that some of the fill soils contained wood, brick, and other debris. These materials should not be allowed to be used in new fill materials. The use of the undercut materials as compacted structural fill will depend on the soil moisture content, and the Contractor's ability to limit contamination of these materials with organic matter or construction debris during undercutting.

Compacted structural fill subgrades should be kept free of ponded water. If springs or other flowing water is present at the compacted structural fill subgrade level, the Contractor should direct water to discharge beyond the fill limits. Recommendations for discharging springs should be provided by the Geotechnical Engineer.

Compacted structural fill subgrades should be free of snow, ice, and frozen soils. If snow, ice, or frozen soils are present at subgrade levels, these materials should be removed as recommended by the Geotechnical Engineer.

Some existing structures present on site will need to be removed before earthwork construction. Therefore, buried foundations and other associated debris may be encountered during grading activities. Existing foundations should be removed to at least 1 ft below the design pavement or new foundation



subgrade level. Existing utilities and drainage structures within the foundation or pavement areas should be removed and replaced with compacted structural fill.

Compacted structural fill subgrades should not be steeper than about 4H:1V. If steeper slopes are present, subgrades should be benched to permit placement of horizontal lifts of fill.

Compacted Fill

Compacted structural fill and backfill in foundation and pavement areas should consist of material classifying SC, SM, SP, SW, GC, GM, GP, or GW according to ASTM D2487. Fill materials should not contain particles larger than three inches, debris such as wood and bricks or organic matter. Some of the on-site soils of Strata A, C, and D can be expected to meet these criteria. Portions of the fill soils of Stratum A are generally not considered suitable for re-use as compacted structural fill due to high plasticity and presence of construction debris.

Compacted structural fill should be placed in maximum 8-inch thick horizontal, loose lifts. Fill should be compacted to at least 95 percent of the maximum dry density per ASTM D698 (Standard Proctor).

Backfill placed in excavations, trenches, and other areas that large compaction equipment cannot access should be placed in maximum 6-inch thick lifts. Backfill should meet the material, placement, and compaction requirements outlined above.

Successful re-use of the excavated, on-site soils as compacted structural fill will depend on their natural moisture contents during excavation. Laboratory test results indicate soils encountered in proposed borrow areas are wet of the optimum moisture content. Scarifying and drying of these soils should be anticipated to achieve the recommended compaction. Drying of these soils will likely result in some delays, and may not be possible during cooler, wetter weather, or where there is limited area to spread them out to dry. We recommend that the earthwork be performed during the warmer, drier times of the year.

Shaft Foundations

We anticipate that the 25 ft tall tapered steel poles will be founded on short drilled pier foundations, generally bearing in the fill soils of Stratum A. We recommend that an allowable shaft friction value of 0.5 ksf, and an allowable end bearing resistance of 2 ksf be used for the design of the drilled pier foundations. These design parameters are for use in the design of compressive resistance and uplift resistance of the drilled shafts. These values were developed using a factor of safety of 2.5 for unit shaft side resistance and a factor of safety of 3.0 for tip resistance of the drilled shaft. Settlements of less than about 1 inch are anticipated.

We recommend that the method described in IBC Section 1807.3.2.1 be used for the lateral capacity calculations of the drilled shafts. A lateral bearing capacity of 200 psf, times the depth of embedment can be used for the light poles constructed in the firm density sands of Stratum A.

However, soft consistency clay soils were encountered in the northwest corner of the site. Light pole foundations constructed in these soils will likely require undercut of 2 to 3 ft at their base, and backfill with



VDOT No. 57 to achieve the end bearing capacity noted above. A lateral bearing capacity of 100 psf, times the depth of embedment should be used for light poles constructed in the softer clays of Stratum A.

Spread Footings

We consider spread footings suitable for support of the proposed structures. Footings should be founded on suitable existing fill or natural soils consisting of the soils of Strata A or C, and/or on new compacted structural fill. Compacted structural fill should meet the requirements outlined in the Site Grading and Earthwork section of this report. We recommend footings supported on these materials be designed for a net allowable soil bearing pressure of 2 ksf. This bearing pressure provides a factor of safety against general bearing capacity failure of at least 3.0. A lateral sliding resistance (coefficient of friction) or 0.3 can be considered between the bottom of the concrete and the granular soils of Stratum A, B, or C.

The above allowable soil bearing pressure may be increased by 33 percent for wind and seismic loads when used in conjunction with load combinations defined in IBC 2012 Section 1605.3.2, Alternative Basic Load Combinations for use with allowable stress design. This increase is not applicable for other allowable stress load combinations, strength design, or load and resistance factor design.

We anticipate suitable subgrade soils will be encountered at shallow depths (less than 2 ft) below the proposed finished grades, except possibly in the northwest corner of the site. All footing subgrades should be observed by the Geotechnical Engineer prior to placement of concrete to evaluate if subgrade materials are as anticipated.

If unsuitable soils are encountered at the design bearing grade, these soils should be removed and replaced as recommended by the Geotechnical Engineer. Unsuitable soils should be replaced with VDOT No. 57 stone.

Settlements of shallow foundations supported on suitable natural soils and on properly placed compacted structural fill are not expected to exceed about one inch. Differential settlements between similarly loaded footings are not expected to exceed about half this value.

Column should be at least 24 inches wide, respectively, for shear considerations. Footings should be founded at least 2 ft below final exterior grades for frost protection.

Below Grade Walls

Below-grade walls for the fountain vault will either be braced or unbraced. Walls should be designed considering equivalent fluid pressure, gef, as shown in Figure 3. Equivalent fluid pressure factors are presented in Table 1 for the respective backfill conditions. Where applicable, the design should consider surcharge loads using a rectangular earth pressure distribution as shown in Figure 3. The surcharge pressure ordinate should be obtained by multiplying the surface surcharge pressure, q, by the factor in Table 1 for the respective backfill condition. Horizontal forces on the wall should be resisted by friction acting on the base of the wall as shown on Figure 3. A friction factor of 0.3 should be used for the design.



Table 1: Recommended Design Parameters for Walls

Wall Type Backfill Materials

Equivalent Fluid Pressure Factor

(gef)

Surcharge Pressure

Factor Braced On-site 50H 0.40q

Cantilevered On-site 35H 0.25q

The above parameters consider a horizontal ground surface behind and in front of the walls. We should be contacted to provide alternative parameters if sloping ground surface conditions are anticipated.

These design parameters do not consider hydrostatic pressure since we recommend subdrainage behind the walls. Below-grade walls should be backfilled as recommended below. Below-grade walls should be damp proofed.

Backfill materials for walls designed considering free-draining backfill should consist of non-plastic material classifying SP-SM, SW-SM, SP, SW, GW-GM, GP-GM, GP, or GW according to ASTM D2487. This classification includes open-graded crushed stone such as VDOT No. 78 or No. 57. Free-draining backfill should be placed in the zone extending from the base of the wall upwards at 45 degrees. Backfill materials for walls designed considering on-site materials used for backfill should consist of material classifying SC, SM, SP, SW, GP or GW according to ASTM D2487.

The Contractor should place backfill in maximum 6-inch thick loose lifts, and compact each lift to at least 95 percent of maximum dry density according to ASTM D698 (Standard Proctor), or to at least 70 percent relative density according to ASTM D4253 and D4254. Only light hand-operated equipment should be used to compact backfill against walls. The Structural Engineer of Record should approve the size of the compaction equipment. If backfill consists of open-graded aggregate, the Contractor should place backfill in maximum 12-inch thick lifts, and compact each lift using suitable vibratory equipment.

Earth pressure recommendations provided do not include hydrostatic pressure since subdrainage will be provided behind the below-grade walls. Subdrainage should consist of perimeter subdrains located on top of the wall footing, next to the wall. Subdrains should consist of four-inch slotted, corrugated polyethylene tubing according to ASTM F405 surrounded by at least six inches of filter drainage material. Subdrains should drain by gravity to an outlet, or to a sump or storm sewer.

Geocomposite drainage panels consisting of Miradrain G100N or equivalent should be installed on all below-grade walls when on-site soils are used as wall backfill. Drainage panels should be placed along the entire wall face to within 1.5 ft of finished grade. The Contractor should bind the edges of the panels with drainage geotextile to limit the potential for soil intrusion into the drainage system.

Drainage filter material should consist of VDOT No. 57 aggregate. Drainage geotextile should consist of a non-woven geotextile such as Mirafi 140N or equivalent.

Pavements

The Contractor should prepare pavement subgrades and place compacted structural fill for pavement support as described in the Site Grading and Earthwork section of this report. Dense-graded aggregate



placed as pavement base course should be compacted to at least 100 percent of maximum dry density according to ASTM D698, Standard Proctor. Dense-graded aggregate should be placed in maximum 6-inch thick loose lifts.

Final pavement subgrades should be proofrolled under the observation of the Geotechnical Engineer immediately prior to placing subbase or base course aggregate to evaluate their suitability to support the pavement.

A design CBR value of 7 should be used for the design of pavement sections for this site. This design CBR value represents two-thirds of the average laboratory value.

We recommend that reinforced concrete pavement be designed based on a modulus of subgrade reaction value, k, of 125 pci. The recommended modulus value is for a 1-ft-square plate. Some pavement design software may consider different definitions of k for input. The Civil Engineer should contact our office if their software considers a different definition of k. Adequate control of surface drainage will be a very important consideration for the overall performance of the pavement design. The area surrounding pavements should be graded to direct surface water away from paved areas. Utility excavations within pavement areas should be backfilled with compacted structural fill. We recommend providing pavement subdrains in cut areas where grades slope toward the pavement. Pavement subdrains should discharge into a storm sewer. Perched groundwater levels may develop at this site, especially if landscaped areas are irrigated. A perched groundwater condition would increase the risk of damage to the pavements. Therefore, we recommend that subdrains be installed below landscaped areas next to the pavements to control water that has infiltrated and accumulated. These underdrains should connect to a storm sewer.

CONSTRUCTION CONSIDERATIONS

Site Grading and Earthwork

The on-site soils are susceptible to moisture changes, will be easily disturbed, and will be difficult to compact under wet weather conditions. Drying and reworking of the soils are likely to be difficult during periods of wet months. We recommend that the earthwork phases of this project be performed during the warmer, drier times of the year to limit the potential for disturbance of on-site soils.

Traffic on stripped or undercut subgrades should be limited to reduce disturbance of underlying soils. The Contractor should provide site drainage to maintain subgrades free of water and to avoid saturation and disturbance of the subgrade soils before placing compacted structural fill, pavement base course or moisture barrier material. This site drainage will be important during all phases of the construction work. The Contractor should be responsible for reworking of subgrades and compacted structural fill that were initially considered suitable but were later disturbed by equipment and/or weather.

Considering the potential for undercut of existing fill soils we recommend establishing an allowance for undercut and backfill of unsuitable fill or foundation subgrades. The contract bid documents should



include add/deduct unit rates related to undercut of unsuitable soils. As noted in previous sections we have also recommended establishing unit rates in the bid documents for the use of geotextiles and select fill materials for use in remediating unsuitable subgrade soils. A list of the proposed unit rates and corresponding quantities for establishing a value is included in the table below.

Table 1: Add/Deduct Unit Prices and Suggested Quantities

Bid Item Allowance or Quantity Undercut and disposal off site 500 cy Off-site borrow meeting compacted structural fill requirements 500 cy VDOT No. 10 Stone 300 cy VDOT No. 57 Stone 200 cy VDOT No. 3 Stone 200 cy VDOT Size 21A/B Stone 100 cy Geogrid (Tensar 140X or equivalent) 400 sy Separation Geotextile (Mirafi 500X or equivalent) 400 sy

As we noted in a previous section of this report, if wet cut soils or subgrades are encountered, air drying those materials is generally only practical during the warmer, drier times of the year (May through October). The contractor would also need to employ the proper equipment (large farm disc or windrow) and have adequate space to effectively dry on site soils. The cost for this mechanical manipulation of wet soils could be included in the contract price by stipulating that wet on site soils will need to be dried adequately to achieve the required compaction. Alternatively, a unit rate could be established for drying on site soils. It has been our experience that establishing this unit rate based on a volume unit is difficult. We recommend a time and materials unit rate that establishes an hourly rate for the operator and equipment required to adequately dry a lift of fill. It is important to specify that proper equipment is used and that the unit rate applies only when the equipment is in use. Proper equipment could be defined as a farm disc and tractor capable of scarifying a lift of fill or undisturbed subgrade to a minimum depth of 8 inches.

The contractor should be prepared to modify existing fill subgrades through ground improvement techniques including shallow undercut and replacement with crushed stone, adding geogrid, and/or adding geotextile fabric to improve existing subgrades. Specific recommendations for subgrade remediation will depend on the ground and weather conditions at the time the work is performed. Those recommendations should be made by the Geotechnical Engineer during construction.

Other than at the ground surface, buried obstructions were not encountered during drilling of the test borings. Considering the depth of fill encountered in the borings and the historic urban uses of the site it is likely that some obstructions (previous foundations, utilities, basement walls, etc.) will be encountered during excavation on the site. This potential increases for deeper excavations such as light pole foundations and the pool vault. Unit prices should be established in the bid documents for removal of buried obstructions and disposal off site.



Drilled Shafts

Drilled shafts should be constructed according to good engineering practice. Since the drilled shafts will be drilled through fill materials, difficult drilling should be anticipated. We believe the soils can be excavated with a soil auger fitted with carbide teeth. Some undercut, or overexcavation or drilled piers may be necessary in the northwest corner of the site based on the available test boring data. The shafts should be filled with concrete as the casing is withdrawn. If shafts are installed to a depth greater than 8 ft, a minimum concrete head of 8 ft above the bottom of the casing should be provided so that discontinuities do not develop in the drilled shaft and to limit intrusion of soil into the shaft. The Geotechnical Engineer should record the concrete volume. A slump of 6 inches (± 1 inch) is recommended for drilled shaft concrete to reduce the possibility of the concrete arching within the casing during withdrawal.

Spread Footings

The Contractor should exercise care during excavation for spread footings so that as little disturbance as possible occurs at the foundation level. The Contractor should carefully clean loose or soft soils from the bottom of the excavation before placing concrete. A Geotechnical Engineer from our firm should observe footing subgrades prior to concrete placement to evaluate whether subgrade soils are as anticipated in this report. Undercut of some foundation subgrades should be anticipated, particularly in the northwest corner of the site. Undercut depths will generally be limited to 2 to 3 ft below the design bearing grade. Footing undercuts should be backfilled with VDOT No. 57 stone.

The potential for variation of moisture content in foundation soils is probably greatest during construction. If the moisture content of foundation soils increases or decreases during construction, a moisture-related change in volume will likely occur as these soils return to their natural moisture content. Therefore, prompt placement of concrete, backfilling, and grading are very important for proper foundation performance.

To protect bearing materials from deteriorating, three-inch mud-mats consisting of lean concrete should be placed over them immediately after excavation and evaluation of spread footing subgrades. Forms may be used if necessary, but less subgrade disturbance is expected if excavations are made to the required dimensions, and concrete is placed against the soil. If footings are formed, the forms should be pulled and the excavation backfilled as soon as possible. Water should not be allowed to pond along the outside of footings for long periods of time.

Engineering Services During Construction

The engineering recommendations provided in this report are based on the information obtained from the subsurface exploration and laboratory testing. However, conditions on the site may vary between the discrete locations observed at the time of our subsurface exploration. The nature and extent of variations between borings may not become evident until during construction.

To account for this variability, we should provide professional observation and testing of subsurface conditions revealed during construction as an extension of our engineering services. These services will also help in evaluating the contractor's conformance with the plans and specifications in accordance with



building code requirements. Because of our unique position to understand the intent of the geotechnical engineering recommendations, retaining Schnabel for these services will allow the owner to receive consistent service throughout the project construction.

General Specification Recommendations

An allowance should be established to account for possible additional costs that may be required to construct earthwork and foundations as recommended in this report. Additional costs may be incurred for a variety of reasons including variation of soil between borings, greater than anticipated unsuitable soils, need for borrow fill material, wet on-site soils, obstructions, temporary dewatering, etc.

We recommend that the construction contract include unit prices for scarifying and drying wet and/or loose subgrade soils, and provide an allowance for this work. In addition, the construction contract should include an allowance for undercutting soft or loose, near-surface soils, and replacement with compacted structural fill. Add/deduct unit prices should also be established in the contract so adjustments can be made for the actual volume of materials handled.

We also recommend an allowance be established for installation of pavement subdrains. Add/deduct unit prices should be provided so adjustments for the actual length of drains installed can be made.

The project specifications should indicate the Contractor's responsibility for providing adequate site drainage during construction. Inadequate drainage will most likely lead to disturbance of soils by construction traffic and increased volume of undercut.

This report may be made available to prospective bidders for informational purposes. We recommend that the project specifications contain the following statement:

Schnabel Engineering, LLC has prepared this geotechnical engineering report for this project. This report is for informational purposes only and is not part of the contract documents. The opinions expressed represent the Geotechnical Engineer’s interpretation of the subsurface conditions, tests, and the results of analyses performed. Should the data contained in this report not be adequate for the Contractor's purposes, the Contractor may make, before bidding, independent exploration, tests and analyses. This report may be examined by bidders at the office of the Owner, or copies may be obtained from the Owner at nominal charge.

Additional data and reports prepared by others that could have an impact upon the Contractor's bid should also be made available to prospective bidders for informational purposes.

LIMITATIONS

We based the analyses and recommendations submitted in this report on the information revealed by our exploration. We attempted to provide for normal contingencies, but the possibility remains that unexpected conditions may be encountered during construction.

This report has been prepared to aid in the evaluation of this site and to assist in the design of the project. It is intended for use concerning this specific project. We based our recommendations on information on the site and proposed construction as described in this report. Substantial changes in loads, locations, or



grades should be brought to our attention so we can modify our recommendations as needed. We would appreciate an opportunity to review the plans and specifications as they pertain to the recommendations contained in this report, and to submit our comments to you based on this review.

We have endeavored to complete the services identified herein in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing in the same locality and under similar conditions as this project. No other representation, express or implied, is included or intended, and no warranty or guarantee is included or intended in this report, or other instrument of service.

We appreciate the opportunity to be of service for this project. Please call us if you have any questions regarding this report.

Sincerely, SCHNABEL ENGINEERING, LLC Kevin D. Pocta, EIT Senior Staff Engineer Paul E. Diggs, PE Principal

KDP:PED:dah Figures Appendix A: Subsurface Exploration Data Appendix B: Soil Laboratory Test Data

dharmon

Kevin Pocta

dharmon

Paul Diggs

dharmon

Paul Diggs

May 5, 2016 Schnabel Engineering, LLC Project 16C13048 ©2016 All Rights Reserved

FIGURES

Figure 1: Site Vicinity Map Figure 2: Boring Location Plan Figure 3: Earth Pressure Detail

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TITLE

PROJECT NO. 16C13048.00

SITE VICINITYMAP

FIGURE 1

Sources: Esri, HERE, DeLorme, USGS, Intermap, increment P Corp., NRCAN, Esri Japan,METI, Esri China (Hong Kong), Esri (Thailand), MapmyIndia, © OpenStreetMap contributors, andthe GIS User CommunitySource: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS,

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© Schnabel Engineering, 2016. All Rights Reserved.

kpocta

Text Box

17th STREET MARKET 100 NORTH 17th STREET RICHMOND, VIRGINIA

UT

C

UT

C

UT

C

B-01

B-02

B-03

B-06

B-05

B-04

N. 17TH STREET

N. 17TH STREET

E. M

AIN

S

TR

EE

T

2

00 30' 60'

SCALE: 1"=30'

17TH STREET MARKET

100 NORTH 17TH STREET

RICHMOND, VIRGINIA

Base Plan Provided by Baskerville on March 30, 2016.

BORING LOCATION PLAN

16C13048

K. POCTA

P. DIGGS APR 2016

Figure Name:

Project Number:

Done:

Reviewed:

Figure Number:

Date:

LEGEND

APPROXIMATE BORING LOCATION

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PRESSURE

CONDITION

AT REST

(BRACED)

ACTIVE

(UNBRACED)

BACKFILL

SM OR BETTER

W/LESS THAN 20%

PASSING NO. 200

SIEVE

SM OR BETTER

W/LESS THAN 20%

PASSING NO. 200

SIEVE

EQUIVALENT

FLUID PRESSURE (A)

50H psf

35H psf

COEFFICIENT (B)

0.40q

0.25q

A

q, SURCHARGE

(PSF)

SLOPE AS REQUIRED

BY OSHA

FOR STABILITY

EARTH PRESSURE RECOMMENDATIONS FOR

BRACED AND UNBRACED WALLS BELOW GRADE

NOT TO SCALE

PERIMETER SUBDRAIN

B

H

GEOCOMPOSITE

DRAINAGE PANEL

GROUND

SURFACE

F = 0.35

Figure Name: Done:

Project Number: Reviewed:

Figure Number:

Date:

17TH STREET MARKET

100 NORTH 17TH STREET

RICHMOND, VIRGINIA

EARTH PRESSURE DETAIL

16C13048

K. POCTA

P. DIGGS

3

MAY 2016

G:\2

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1 - 2

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APPENDIX A

SUBSURFACE EXPLORATION DATA

Subsurface Exploration Procedures General Notes for Subsurface Exploration Logs Identification of Soil Boring Logs, B-01 through B-06


SUBSURFACE EXPLORATION PROCEDURES

Test Borings

The borings are advanced by turning a continuous flight auger with a center opening of 2¼ inches. A plug device blocks off the center opening while augers are advanced. Cuttings are brought to the surface by the auger flights. Sampling is performed through the center opening in the hollow stem auger, by standard methods, after removal of the plug. Usually, no water is introduced into the boring using this procedure.

Standard Penetration Test Results

The numbers in the Sampling Data column of the boring logs represent Standard Penetration Test (SPT) results. Each number represents the blows needed to drive a 2-inch O.D., 1⅜-inch I.D. split-spoon sampler 6 inches, using a 140-pound hammer falling 30 inches. The sampler is typically driven a total of 18 or 24 inches. The first 6 inches are considered a seating interval. The total of the number of blows for the second and third 6-inch intervals is the SPT “N value.” The SPT is performed according to ASTM D1586.

Soil Classification Criteria

The group symbols on the logs represent the Unified Soil Classification System Group Symbols (ASTM D2487) based on visual observation and limited laboratory testing of the samples. Criteria for visual identification of soil samples are included in this appendix. Some variation can be expected between samples visually classified and samples classified in the laboratory.

Pocket Penetrometer Results

The values following “PP=” in the sampling data column of the logs represent pocket penetrometer readings. Pocket penetrometer readings provide an estimate of the unconfined compressive strength of fine-grained soils.

Water Observation Wells

A temporary water observation well was installed in Boring B-03 by inserting a hand-slotted, 1¼-inch PVC pipe in the boring. The pipe was capped and the area surrounding the pipe was backfilled with cuttings from the boring.

Boring, Hand Auger and Test Pit Locations and Elevations

Borings were located using sub-meter GPS equipment. Approximate boring locations are shown on Figure 2. Ground surface elevations at the boring locations were obtained from the site topographic plan and are indicated on the boring logs. Locations and elevations should be considered no more accurate than the methods used to determine them.


GENERAL NOTES FOR SUBSURFACE EXPLORATION LOGS

1. Numbers in sampling data column next to Standard Penetration Test (SPT) symbols indicate

blows required to drive a 2-inch O.D., 1⅜-inch I.D. sampling spoon 6 inches using a 140 pound hammer falling 30 inches. The Standard Penetration Test (SPT) N value is the number of blows required to drive the sampler 12 inches, after a 6 inch seating interval. The Standard Penetration Test is performed in general accordance with ASTM D1586.

2. Visual classification of soil is in accordance with terminology set forth in “Identification of Soil.” The ASTM D2487 group symbols (e.g., CL) shown in the classification column are based on visual observations.

3. Estimated water levels indicated on the logs are only estimates from available data and may vary with precipitation, porosity of the soil, site topography, and other factors.

4. Refusal at the surface of rock, boulder, or other obstruction is defined as an SPT resistance of 50 blows for 1 inch or less of penetration.

5. The logs and related information depict subsurface conditions only at the specific locations and at the particular time when drilled or excavated. Soil conditions at other locations may differ from conditions occurring at these locations. Also, the passage of time may result in a change in the subsurface soil and water level conditions at the subsurface exploration location.

6. The stratification lines represent the approximate boundary between soil and rock types as obtained from the subsurface exploration. Some variation may also be expected vertically between samples taken. The soil profile, water level observations and penetration resistances presented on these logs have been made with reasonable care and accuracy and must be considered only an approximate representation of subsurface conditions to be encountered at the particular location.

7. Key to symbols and abbreviations:

S-1, SPT Sample No., Standard Penetration Test 5+10+1 Number of blows in each 6-inch increment

LL Liquid Limit MC Moisture Content (percent) PL Plastic Limit PP Pocket Penetrometer Reading (tsf) %Passing#200 Percent by weight passing a No. 200 Sieve

IDENTIFICATION OF SOIL I. DEFINITION OF SOIL GROUP NAMES (ASTM D2487) SYMBOL GROUP NAME

Coarse-Grained Soils More than 50% retained on No. 200 sieve

Gravels – More than 50% of coarse fraction retained on No. 4 sieve Coarse, ¾” to 3” Fine, No. 4 to ¾”

Clean Gravels Less than 5% fines

GW WELL GRADED GRAVEL

GP POORLY GRADED GRAVEL

Gravels with fines More than 12% fines

GM SILTY GRAVEL GC CLAYEY GRAVEL

Sands – 50% or more of coarse Fraction passes No. 4 sieve Coarse, No. 10 to No. 4 Medium, No. 40 to No. 10 Fine, No. 200 to No. 40

Clean Sands Less than 5% fines

SW WELL GRADED SAND

SP POORLY GRADED SAND

Sands with fines More than 12% fines

SM SILTY SAND SC CLAYEY SAND

Fine-Grained Soils 50% or more passes the No. 200 sieve

Silts and Clays – Liquid Limit less than 50 Low to medium plasticity

Inorganic CL LEAN CLAY ML SILT

Organic OL ORGANIC CLAY ORGANIC SILT

Silts and Clays – Liquid Limit 50 or more Medium to high plasticity

Inorganic CH FAT CLAY MH ELASTIC SILT

Organic OH ORGANIC CLAY ORGANIC SILT

Highly Organic Soils Primarily organic matter, dark in color and organic odor PT PEAT

II. DEFINITION OF SOIL COMPONENT PROPORTIONS (ASTM D2487) Examples

Adjective Form

GRAVELLY SANDY

>30% to <50% coarse grained component in a fine-grained soil

GRAVELLY LEAN CLAY

CLAYEY SILTY

>12% to <50% fine grained component in a coarse-grained soil

SILTY SAND

“With” WITH GRAVEL WITH SAND

>15% to <30% coarse grained component in a fine-grained soil

FAT CLAY WITH GRAVEL

WITH GRAVEL WITH SAND

>15% to <50% coarse grained component in a coarse-grained soil

POORLY GRADED GRAVEL WITH SAND

WITH SILT WITH CLAY

>5% to <12% fine grained component in a coarse-grained soil

POORLY GRADED SAND WITH SILT

III. GLOSSARY OF MISCELLANEOUS TERMS

SYMBOLS ............................ Unified Soil Classification Symbols are shown above as group symbols. A dual symbol “-“ indicates the soil belongs to two groups. A borderline symbol “/” indicates the soil belongs to two possible groups.

FILL ........................................ Man-made deposit containing soil, rock and often foreign matter. PROBABLE FILL................... Soils which contain no visually detected foreign matter but which are suspect with regard

to origin. DISINTEGRATED ROCK (DR) ........................................

Residual materials with a standard penetration resistance (SPT) between 60 blows per foot and refusal. Refusal is defined as a SPT of 100 blows for 2” or less penetration.

PARTIALLY WEATHERED ROCK (PWR) .........................

Residual materials with a standard penetration resistance (SPT) between 100 blows per foot and refusal. Refusal is defined as a SPT of 100 blows for 2” or less penetration.

BOULDERS & COBBLES ..... Boulders are considered rounded pieces of rock larger than 12 inches, while cobbles range from 3 to 12 inch size.

LENSES ................................. 0 to ½ inch seam within a material in a test pit. LAYERS ................................. ½ to 12 inch seam within a material in a test pit. POCKET ................................ Discontinuous body within a material in a test pit. MOISTURE CONDITIONS ..... Wet, moist or dry to indicate visual appearance of specimen. COLOR .................................. Overall color, with modifiers such as light to dark or variation in coloration.

FILL

GC

SM

19.719.519.318.9

15.7

13.0

5.0

0.30.50.71.1

4.3

7.0

15.0

S-01, SPT31+10+9REC=11", 61%

S-02, SPT9+9+14REC=12", 67%

S-03, SPT18+34+38REC=15", 83%

S-04, SPT10+8+11REC=14", 78%

S-05, SPT5+9+12REC=14", 78%

S-06, SPT5+12+16REC=13", 72%

Brick; 3.5 inches

Sand leveling course, 2 inches

Asphalt; 3 inches

Dense graded aggregate; 4 inches

FILL, sampled as clayey sand, fine tocoarse grained sand; moist, orangishbrown, contains gravel, and brickfragments

CLAYEY GRAVEL WITH SAND, fineto coarse gravel; moist, orangish brown

SILTY SAND, fine to coarse grainedsand; moist, light gray, contains mica

FILL

TERRACEAugersgrinding/scraping.

RESIDUUM

A

C

D

MC = 14.8%

MC = 22.5%

Bottom of Boring at 15.0 ft.Boring terminated at selected depth.Boring backfilled with cuttings and borehole plug upon completion.

Encountered

Completion

Casing Pulled

4/14

4/14

4/14

9:01 AM

9:01 AM

9:23 AM

None

Dry

Dry

---

---

---

---

---

6.5'

Schnabel Representative: K. Pocta

Total Depth: 15.0 ft

Method: 2-1/4" ID Hollow Stem Auger

Equipment: CME-55 (Truck)

Ground Surface Elevation: 20± (ft)

Contractor: Ayers & Ayers, Inc.Powhatan, Virginia

Contractor Foreman: M. White

Hammer Type: Safety Hammer (140 lb)

Dates Started: 4/14/16 Finished: 4/14/16

Location: See Location Plan

Date CavedDepthTime CasingGroundwater Observations

17th Street Market100 North 17th StreetRichmond, Virginia

SYMBOL

Contract Number: 16C13048Sheet: 1 of 1

SAMPLING

DEPTH

5

10

15

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:

DATAMATERIAL DESCRIPTION

B-01

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6

FILL

GC

SM

20.320.219.919.5

16.5

13.5

5.5

0.20.30.61.0

4.0

7.0

15.0

S-01, SPT30+16+11REC=10", 56%

S-02, SPT6+5+12REC=14", 78%

S-03, SPT11+14+14REC=12", 67%

S-04, SPT14+12+16REC=6", 33%

S-05, SPT6+17+23REC=17", 94%

S-06, SPT7+18+20REC=16", 89%

Brick; 2.5 inches

Sand leveling course, 1 inch

Asphalt; 3 inches


FILL, sampled as sandy lean clay;moist, brown, contains brick fragments

CLAYEY GRAVEL WITH SAND, fineto coarse gravel; moist, orangish brown

SILTY SAND, fine to coarse grainedsand; moist, light orangish gray,contains mica

FILL


RESIDUUM

A

C

D

MC = 17.2%PP = 3.50 tsf


Encountered

Completion

Casing Pulled

4/14

4/14

4/14

10:01 AM

10:01 AM

10:06 AM

None

Dry

Dry

---

---

---

---

---

9.0'













SYMBOL


SAMPLING

DEPTH

5

10

15

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:


B-02

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6

FILL

SC

SM

19.619.419.0

17.4

14.7

5.0

0.40.61.0

2.6

5.3

15.0

S-01, SPT17+18+11REC=10", 56%

S-02, SPT22+30+50/5"REC=10", 59%

S-03, SPT18+19+14REC=8", 44%

S-04, SPT5+10+16REC=14", 78%

S-05, SPT9+15+16REC=16", 89%

S-06, SPT10+18+25REC=18", 100%

Concrete; 4.5 inches

Asphalt; 3 inches


FILL, sampled as silty sand, fine tocoarse grained sand; moist, brownChange: contains brick fragments

CLAYEY SAND WITH GRAVEL, fineto coarse grained sand; moist,orangish brown

SILTY SAND, fine to coarse grainedsand; moist, light gray, contains mica,and fat clay lenses

Change: gray and orangish brown

Change: greenish gray and orangishbrown

FILL


RESIDUUM

A

C

D

LL = 39PL = 14MC = 14.5%% Passing#200 = 24.2

PP = 3.50 tsf

Bottom of Boring at 15.0 ft.Boring terminated at selected depth.Observation well installed upon completion.

Encountered

Completion

Observation Well

Observation Well

Observation Well

4/14

4/14

4/14

4/28

5/4

10:50 AM

10:50 AM

10:57 AM

12:00 AM

1:45 PM

None

Dry

Dry

9.4'

8.0'

---

---

12.8'

12.8'

---

---

---

---

---

---













SYMBOL


SAMPLING

DEPTH

5

10

15

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:


B-03

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6

FILL

FILL

FILL

GC

SM

18.518.117.7

15.0

10.0

0.5

-3.5

-6.0

0.50.91.3

4.0

9.0

18.5

22.5

25.0

S-01, SPT11+16+15REC=10", 56%

S-02, SPT14+10+9REC=16", 89%

S-03, SPT11+11+11REC=14", 78%

S-04, SPT3+3+2REC=14", 78%

S-05, SPT2+1+2REC=9", 50%

S-06, SPT2+2+2REC=16", 89%

S-05, SPT18+16+22REC=10", 56%

S-06, SPT10+12+26REC=16", 89%

Concrete; 5.5 inches

Asphalt; 5.5 inches


FILL, sampled as poorly graded sandwith silt, fine to coarse grained sand;moist, brown

FILL, sampled as silty sand, fine tocoarse grained sand; moist, darkbrown, contains brick fragments, andgravel

FILL, sampled as sandy lean clay;moist, dark gray, contains woodfragments, and brick fragments

Change: wet

CLAYEY GRAVEL WITH SAND, fineto coarse gravel; wet, gray

SILTY SAND, fine to coarse grainedsand; moist, light gray with speckles ofblack, contains mica

FILL

woven geotextileat 3 ft

TERRACE

RESIDUUM

A

C

D

LL = 32PL = 21MC = 28.2%% Passing#200 = 55.1PP = 2.00 tsf

PP = 1.00 tsf


Encountered

Completion

Casing Pulled

4/14

4/14

4/14

11:32 AM

11:46 AM

11:51 AM

13.5'

Dry

Dry

---

---

---

---

---

6.0'













SYMBOL


SAMPLING

DEPTH

5

10

15

20

25

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:


B-04

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6

FILL

SC

SM

17.717.617.116.8

8.0

-0.5

-2.0

0.30.40.91.2

10.0

18.5

20.0

S-01, SPT42+20+14REC=12", 67%

S-02, SPT3+2+2REC=9", 50%

S-03, SPT2+3+2REC=18", 100%

S-04, SPT2+1+3REC=4", 22%

S-05, SPT2+2+5REC=12", 67%

S-06, SPT1+1+2REC=18", 100%

S-07, SPT4+6+8REC=4", 22%

Brick; 3 inches

Sand leveling course, 1 inch

Asphalt; 6 inches


FILL, sampled as sandy fat clay; moist,light gray and orangish brown, containscrushed stone, and brick fragments

CLAYEY SAND, fine to coarse grainedsand; moist, dark gray, containsorganic matter

SILTY SAND, fine to medium grainedsand; moist, greenish gray, containsmica

FILL

ALLUVIUM

RESIDUUM

A

B

D

LL = 64PL = 25MC = 26.7%% Passing#200 = 57.5PP = 1.00 tsfPP = 1.50 tsf

MC = 37.2%PP = 1.50 tsf

PP = 0.50 tsf

MC = 21.1%


Encountered

Completion

Casing Pulled

4/14

4/14

4/14

12:27 PM

12:31 PM

12:35 PM

10.0'

Dry

Dry

---

---

---

---

---

1.5'













SYMBOL


SAMPLING

DEPTH

5

10

15

20

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:


B-05

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6

FILL

FILL

SM

16.5

14.3

9.0

3.5

2.0

4.2

9.5

15.0

S-01, SPT3+4+4REC=10", 56%

S-02, SPT5+11+7REC=8", 44%

S-03, SPT6+8+6REC=4", 22%

S-04, SPT6+4+4REC=12", 67%

S-05, SPT5+9+13REC=12", 67%

Concrete; 24 inches

FILL, sampled as poorly graded sandwith silt, fine to coarse grained sand;moist, brown

FILL, sampled as clayey sand, fine tocoarse grained sand; moist, dark gray,contains wood fragments, and gravel

Change: contains brick fragments

SILTY SAND, fine to coarse grainedsand; moist, greenish gray, containsmica

FILL

Woven geotextileat 4.2 ft

RESIDUUM

A

D

MC = 5.4%

LL = 63PL = 39MC = 22.8%% Passing#200 = 29.1


Encountered

Completion

Casing Pulled

4/14

4/14

4/14

1:21 PM

1:21 PM

1:26 PM

None

Dry

Dry

---

---

---

---

---

5.0'













SYMBOL


SAMPLING

DEPTH

5

10

15

DEPTH(ft)

ELEV(ft)

TESTBORING

LOG

Boring Number:


B-06

REMARKS

Project:

STRATUM TESTS

TE

ST

BO

RIN

G L

OG

16C

130

48 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

200

8_07

_06

.GD

T 5

/5/1

6


APPENDIX B

SOIL LABORATORY TEST DATA

Summary of Laboratory Tests Atterberg Limits Gradation Curves Moisture Density Relation California Bearing Ratio Curve

B-03

2.6 - 5.0

17.4 - 15.0

Bulk

CLAYEY SAND WITH GRAVEL (SC,A-2-6), fine to coarse grained sand, brown RICH C 14.5 39 14 25 24.2 44.2 21.4 126.5 9.2 124.4 8.7 0.8 10.8

B-04

9.0 - 10.5

10.0 - 8.5

Jar

FILL, sampled as sandy lean clay (CL),contains wood fragments, dark gray andbrown

RICH A 28.2 32 21 11 55.1 89.9 0.9 -- -- -- -- -- --

B-05

2.0 - 3.5

16.0 - 14.5

Jar

FILL, sampled as sandy fat clay (CH),contains crushed stone and brick fragments,dark brown and gray

RICH A 26.7 64 25 39 57.5 79.2 3.8 -- -- -- -- -- --

B-06

9.5 - 10.5

9.0 - 8.0

Jar

SILTY SAND (SM), fine to coarse grainedsand, contains mica, dark brown RICH D 22.8 63 39 24 29.1 53.0 0.6 -- -- -- -- -- --

Sheet 1 of 1

BoringNo.

Summary Of Laboratory TestsAppendix B

Description of SoilSpecimen

Project Number: 16C13048

Notes: 1. Soil tests in general accordance with ASTM standards.2. Soil classifications are in general accordance with ASTM D2487(as applicable), based on testing indicatedand visual classification.3. Key to abbreviations: NP=Non-Plastic; -- indicates no test performed

Project:

Elevationft

17th Street Market100 North 17th StreetRichmond, VA

SampleType

SampleDepth

ft

DY

NA

MIC

LA

B S

UM

MA

RY

16C

1304

8 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

201

0_02

_25

.GD

T 4

/28/

16

CB

R D

ry D

ensi

tyA

t C

om

pac

tio

n (

pcf

)

CB

R M

ois

ture

Co

nte

nt

(%)

Max

imu

m D

ryD

ensi

ty (

pcf

)

Str

atu

m

Pla

stic

Lim

it

CB

R V

alu

e

% P

assi

ng

No

. 40

Sie

ve

Op

tim

um

Mo

istu

reC

on

ten

t (%

)

Liq

uid

Lim

it

% P

assi

ng

No

. 20

0 S

ieve

Nat

ura

lM

ois

ture

(%

)

Pla

stic

ity

Ind

ex

% R

etai

ned

No

. 4

Sie

ve

Tes

tin

g L

abo

rato

ry

CB

R P

erce

nt

Sw

ell

0

20

40

60

80

0 20 40 60 80 100

ML

CL

LIQUID LIMIT

B-03

B-04

B-05

B-06

FinesPIPL TestingLab

CLAYEY SAND WITH GRAVEL (SC, A-2-6), fine to coarsegrained sand, brown

FILL, sampled as sandy lean clay (CL), contains woodfragments, dark gray and brown

FILL, sampled as sandy fat clay (CH), contains crushedstone and brick fragments, dark brown and gray

SILTY SAND (SM), fine to coarse grained sand, containsmica, dark brown

LLSpecimen

PLOTTED DATA REPRESENTS SOIL PASSING NO. 40 SIEVE

39

32

64

63

14

21

25

39

25

11

39

24

24

55

58

29

CL-ML MH

CH

Description

RICH

RICH

RICH

RICH

PLA

ST

ICIT

Y I

ND

EX

ATTERBERG LIMITS

2.6 ft

9.0 ft

2.0 ft

9.5 ft

Project: 17th Street Market100 North 17th StreetRichmond, VA

Contract: 16C13048AT

TE

RB

ER

G_L

IMIT

S 1

6C13

048

BO

RIN

G L

OG

S.G

PJ

SC

HN

AB

EL

DA

TA

TE

MP

LAT

E 2

008_

04_2

2.G

DT

4/

28/1

6

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

4 3

GRAIN SIZE IN MILLIMETERS

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

U.S. SIEVE OPENING IN INCHES

200100 1406040

21.4

0.9

3.8

0.6

23 3/41.5 6

CLAYEY SAND WITH GRAVEL (SC, A-2-6), fine to coarsegrained sand, brown

FILL, sampled as sandy lean clay (CL), contains woodfragments, dark gray and brown

FILL, sampled as sandy fat clay (CH), contains crushed stoneand brick fragments, dark brown and gray

SILTY SAND (SM), fine to coarse grained sand, contains mica,dark brown

Specimen

--

--

--

--

LL

U.S. SIEVE NUMBERS

5030

GRADATION CURVES

1/23/8

PL PI Cc Cu

B-03

B-04

B-05

B-06

39

32

64

63

14

21

25

39

25

11

39

24

%Clay

B-03

B-04

B-05

B-06

%Silt%GravelSpecimen

Sample Description

D30

16 2014

%Sand

ASTM D422

ASTM D422

ASTM D422

ASTM D422

54.4

44.0

38.7

70.3

81041

24.2

55.1

57.5

29.1

HYDROMETER

6

Test Method D10

--

--

--

--

0.15

--

--

0.08

D60

0.89

0.09

0.09

0.54

D100

64

9.5

9.5

9.5

RICH

RICH

RICH

RICH

Testing Lab

--

--

--

--

2.6 ft

9.0 ft

2.0 ft

9.5 ft

2.6 ft

9.0 ft

2.0 ft

9.5 ft


Contract: 16C13048SIE

VE

5 S

HE

ET

16C

1304

8 B

OR

ING

LO

GS

.GP

J S

CH

NA

BE

L D

AT

A T

EM

PLA

TE

201

0_02

_25

.GD

T

4/28

/16 fine coarse

COBBLES SILT OR CLAYmedium fine

SANDGRAVELcoarse

117.0

118.0

119.0

120.0

121.0

122.0

123.0

124.0

125.0

126.0

127.0

128.0

129.0

3 5 7 9 11 13 15

ASTM D698 Method C

Comments:Bulk sample obtained from auger cuttings over

the depth interval 1.0 to 5.0 feet

DR

Y D

EN

SIT

Y,

pcf

MOISTURE DENSITY RELATIONSHIP

126.5

9.2

Test Methods:

Sample Description:

Opt. Moisture (%):

Max. Dry Density (pcf):

Assumed Specific Gravity:

Sample Source: B-03, 2.6 ft

CLAYEY SAND WITH GRAVEL (SC,A-2-6), fine to coarse grained sand, brown

2.65

4-26-16Date: DSReviewed By:

WATER CONTENT, %

Testing Lab: RICH

Liquid Limit (LL): 39

Plasticity Index (PI): 25

% Passing # 200 Sieve: 24.2

% Retained #4 Sieve: 21.4


Contract: 16C13048CO

MP

AC

TIO

N 1

6C13

048

BO

RIN

G L

OG

S.G

PJ

SC

HN

AB

EL

DA

TA

TE

MP

LAT

E 2

008_

04_2

2.G

DT

4/

27/1

6

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

0 0.1 0.2 0.3 0.4 0.5

10.8, Soaked

Dry Density Before Soaking (pcf):

Dry Density After Soaking (pcf):

Maximum Dry Density (pcf):

Moisture Content Before Soaking (%):

Moisture Content After Soaking (Avg) (%):

Sample Description:

PENETRATION (INCHES)

CALIFORNIA BEARING RATIO TEST

Surcharge (psf):

CBR:

0.8

50

Optimum Moisture Content (%): 9.2

11.2

8.7

126.5

123.4

124.4

Swell (%):

ST

RE

SS

ON

PIS

TO

N (

psi)

Test Method:

Sample Depth:

B-03

ASTM D1883

Sample Source:

CLAYEY SAND WITH GRAVEL (SC,A-2-6), fine to coarse grained sand, brown

2.6 ft Moisture Content Top Inch After Soak (%): 15.0

RICHTesting Lab:


Contract: 16C13048

Liquid Limit (LL): 39

Plasticity Index (PI): 25

% Passing # 200 Sieve: 24.2

% Retained #4 Sieve: 21.4

CB

R S

ING

LE P

OIN

T 1

6C13

048

BO

RIN

G L

OG

S.G

PJ

SC

HN

AB

EL

DA

TA

TE

MP

LAT

E 2

008_

04_2

2.G

DT

4/2

7/1

6

GEOTECHNICAL ENGINEERING REPORT - … ENGINEERING REPORT . ... Figure 2 included at the end of this...

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Transcript of GEOTECHNICAL ENGINEERING REPORT - … ENGINEERING REPORT . ... Figure 2 included at the end of this...